Weak interactions govern processes such as protein folding, the formation of nucleic acid double helices, and membrane lipid assembly. They determine the spatial conformations of macromolecules and are indispensable forces for organisms to carry out life activities. Terahertz (THz) radiation has emerged as a cutting-edge tool in recent years for elucidating the dynamic behaviors of biomolecules and their regulatory mechanisms, owing to its frequency range highly matching the energy levels of weak interactions in biomolecules (such as hydrogen bonds, van der Waals forces, and metal coordination bonds). This paper summarizes the progress in understanding how terahertz fields influence the weak interactions between protein and biomolecules, focusing on three typical types of weak interactions: protein-metal ion, protein-protein, and protein-organic small molecule interactions.